1. Field of the Invention
The present invention generally relates to an automatic remote meter-reading system for encoding indicative information of meters for electric, gas or water service scattered in a broad area and further encoding an index of a meter centrally set up in an automatic exchange office, in the form of a resistance by a resistive encoder, and detecting an unknown resistance of the encoder through an automatic switching system and/or a controlling system for obtaining an answer back signal by remote-controlling various terminal equipment placed at each terminal of a communication link.
2. Description of the Prior Art
Various automatic remote meter-reading system for providing automatic meter-reading have been proposed to remotely determine a service fee of electric, gas or water service supplied to a consumer by a public service office.
In the past, A.C. signal systems have been employed as a signal system for transmitting meter information to a meter-reading center. However, such systems were difficult to practically apply from an economical viewpoint. Similarly, in the past, D.C. pulse signal systems were used but were also economically difficult to practically apply. In a system for detecting a resistance value representative the digit shown on the meter from a meter-reading center, the meter-reading line length is broadly changed and the condition of a meter-reading line, being affected by weather, is unstable. There have been various problems in this respect in the past.
It has also been considered difficult to economically apply automatic meter-reading of a subscriber's telephone call meters centrally set up in an automatic exchange office. There has been in the past no practical system for the automatic reading of a subscriber's telephone call meter except accumulating the call records in a memory of an electronic switching system, and a remote controlling system which requires an answer-back signal corresponding to the condition of the controlled equipment has been also economically difficult to practically apply for homely use.